The trickiest part of swapping your car’s cabin air filter to a HEPA filter is determining which size filter will fit into your car’s air system. To find out, you can search for cabin-filter sizes in your car’s owner manual or look it up online by either the VIN (vehicle identification number) or your car’s year, make, and model. You can use any HEPA filter (it will be labeled as such) that you know fits your in car. But the Bosch HEPA cabin filter that I used has an online tool to confirm that you’re getting the proper size.
From there, exactly how to change out your air filter varies by car, though in most cases the process will still be simple. In my 2021 Subaru Outback, the filter was located behind the glove box. This is true for many cars, but not all. If you’re not sure, check your car’s manual to find its specific location and how to access it; the spot could be elsewhere along the dash.
If your air filter is located behind the glove box, as mine was, you need to remove the glove box. This task is relatively easy. On my car, I simply cleared my glove box, detached the latch locking it in place, and popped it from its hinges.
With my glove box removed, I could see a cartridge exposed on the wall of the car. Inside—covered in layers of dust and ash that had blown in from the air outside—was my car’s congested, struggling cabin filter. (I recommend wearing a mask and latex gloves for this part, especially if your car has already been through a wildfire.)
I’m not a mechanic, not even an amateur one, but the process of switching the filters was simple. It reminded me of nothing so much as swapping two videotapes in a VCR.
After latching the glove compartment back on its hinges, I flipped on the air conditioner. It kicked on right away, just as strong and evenly flowing as before. (Some online car forums report that HEPA filters can reduce airflow, but I have not noticed any difference.)
In under 15 minutes, without a single tool, I had added a layer of HEPA filtration inside my car.
It’s difficult to anticipate exactly what I’ll need to do to be ready for the next wildfire. I know that next time there will be more things I forget, more things I won’t yet know to do until the problems are already at my doorstep.
But having this small thing done—and knowing that I can do it again, whenever and as often as I need to—makes me feel just a little better prepared for when the next wildfire season comes. And, in the meantime, knowing that my car is better guarded against dust, allergens, and other particulates makes me breathe a little easier, too.
This article was edited by Katie Okamoto and Megan Beauchamp.
